Endoscopes are well known and widely used in the medical field. In general terms, endoscopes can be characterized as either rigid or flexible. Typically, rigid endoscopes comprise an elongated shaft housing an optical system which conveys light rays from the distal end of the shaft to an ocular positioned at the proximal end of the shaft. At times, medical practitioners directly view the inside of a body cavity via the endoscope ocular. Primarily, however, a hand-held, ruggedized camera is detachably affixed to the endoscope ocular to ultimately present images representative of the endoscope field of view on a surgical display/monitor.
Typically, the camera (also known as a camera head) includes a solid-state image sensor which converts detected light rays into electronic signals representative of the endoscope field of view. Additionally, some rigid endoscopes have integrated imagers which obviate the need for a separate camera head. Endoscopes with integrated imagers (both rigid and flexible) are known in the field as video endoscopes. Video endoscopes, as with detachable camera heads, are typically either wired or wirelessly in communication with a camera control unit (“CCU”). CCU's receive, from the camera head or video endoscope, the electronic signals representative of the endoscope field of view.
Video systems used with endoscopes generally provide the capability to view live images representative of an endoscope distal tip field of view while the endoscope shaft is inserted into the patient. Some video systems used with endoscopes also provide capability for the user to capture and store still images, as well as record moving images, i.e., video, of the viewing field. To do so, such video systems generally have an image capture button that is pressed by the surgeon in order to capture a still image or to start/stop recording video. Typically, the image capture button is located on the camera head or the video endoscope itself to be directly under the practitioner's control within the operative sterile field.
For example, U.S. Patent Application Publication No. 2007/0177010 describes an endoscope having a freeze recording button that captures and records a still image at the instant the button is pressed. U.S. Pat. No. 5,740,801 describes an endoscopy system including a still frame buffer that temporarily stores an image obtained by an image input device when a freeze command is received.
A problem with conventional still image capture techniques is that the action of pressing the image capture button, located either on a camera head or video endoscope, tends to cause the endoscope and camera head to move, thus distorting the still image. Even the slightest lateral movement of the endoscope/camera head can typically translate into a substantial corresponding movement of the distal tip of the endoscope, which can induce significant captured still image blur and distortion. Typically, flexible endoscopes do not suffer from captured still image blurring or distortion due to lateral endoscope/camera head movement, because due to the flexible shaft the lateral movements are not transferred to the distal tip of the endoscope. However, longitudinal movement of the endoscope/camera can also induce still image blur or distortion during capture. If, while striking the still image capture button, the practitioner also pulls the endoscope/camera head in a proximal direction, the distal tip of the endoscope may correspondingly move proximally thus inducing blur or distortion. In addition to captured still image blur or distortion caused by endoscope/camera head movement, there is inevitably a delay between the time that a user decides to capture a still image, and the actual time at which the image capture function is executed. Thus, the still image captured may not include what the user intended when the decision was made to capture the still image.
Thus, it is desired to provide an improved image capture method and system which overcomes these problems.